IBM Watson Health just inked its fourth major deal in a move to add healthcare-spending analysis to its suite of products.

IBM Watson Health on Thursday announced the $2.6 billion acquisition of Truven Health Analytics, a company that collects data to find ways to treat patients more effectively while spending less, a concept often known as "value-based care."

The idea with "value-based care" is that instead of getting paid based on the number of people that come to a hospital, doctors have a financial incentive to do more to ultimately help the patient feel better faster. That way, healthcare providers are paid to keep people healthy and help improve the condition of people living with chronic conditions like diabetes in an evidence-based way. To do that, Truven's been tracking everything from drug prices to hospital performance to employee compensation.

Watson is a supercomputer that can process huge amounts of data to do everything from giving you recipes to make dinner to helping out your fantasy baseball team. In healthcare, it's already working to help doctors treat diabetes, fight cancer and monitor pregnancy by analyzing medical studies and other research data.